Some buildings, such as chalets, garages, shelters, or barns, possess wall panels (for outside or inside walls) that are constituted by assembling together a series of elongate wooden planks of substantially rectangular section which are placed horizontally in a vertical plane and which are superposed edge to edge. Panels made in this way are juxtaposed and interconnected in line with one another via their side edges so as to form a continuous wall, or else at right angles (using L, T, and X brackets).
Superposed planks can be assembled together and panels formed by superposed planks can be fastened together by an ancient method of half-thickness lapping which consists in forming notches in the ends of the planks and in engaging the ends of adjacent planks so that the notches are received in one another.
More recently, special assembly devices have been proposed to reduce building costs and to improve the mechanical characteristics of a building. Such assembly devices comprise mainly vertical uprights fitted with means for fastening the ends of planks to the uprights.
In particular, from French patent No. 2 682 974, a device is known in which each vertical upright is a continuous section member, and the means for fastening the upright with each series of planks forming the same panel are implemented in the form of a vertical slideway obtained by recessing one of the faces of the vertical upright and by engaging the end of each plank therein. The planks are thus stacked edge to edge to form a wall panel. A plurality of slideways can be provided on different faces of the vertical upright so as to assemble together a plurality of series of superposed planks constituting a plurality of wall panels which are thus connected together at an angle or in line with one another.
A drawback of that device lies in the fact that the wall formed by the stack of edge-to-edge planks is subjected to the large dimensional variations undergone by the wood constituting the planks as a function of atmospheric conditions, and in particular as a function of the degree of humidity of the ambient air. Since wood fibers are mainly longitudinal, these dimensional variations are particularly perceptible across the planks, i.e. vertically.
Also known, from document FR 2 556 022, is an assembly device in which the means for linking the vertical upright with the planks are implemented in the form of a series of tenons secured to the vertical upright and extending perpendicularly therefrom in a common vertical plane to co-operate with mortises formed in the corresponding ends of the planks.
That kind of device makes it possible for the wall panel constituted by each stack of planks to be insensitive to the dimensional variations of the wood as a function of atmospheric conditions.
The superposed planks are no longer stacked one on another, but on the contrary they are secured in vertical position to the vertical upright by means of the tenons with which they are associated. The vertical pitch of the planks is thus determined by the pitch of the tenons, thereby leaving the planks to move independently from one another, expanding or contracting freely depending on atmospheric conditions and without such dimensional variations affecting the wall panel they constitute. In addition, this makes it possible to build a building that is several stories high.
Nevertheless, a major drawback remains: it can be difficult to assemble the vertical upright to the planks. In particular, it is not practical on site to envisage installing a wooden plank between two vertical uprights that are already secured to the ground without providing other arrangements, such as a notch formed in one of the ends of the plank to give the tenon lateral access to the corresponding mortise. However, such arrangements increase manufacturing costs and run the risk of weakening the structure.